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The W9 was an American nuclear artillery shell fired from a special 280 mm howitzer. It was produced starting in 1952 and all were retired by 1957, being superseded by the W19.
The W9 was 11 inches (280 mm) in diameter, 54.8 in (1,390 mm) long, and weighed 850 lb (390 kg). It had an explosive yield of 15 kt (63 TJ ).
The W9 was a gun-type nuclear weapon, using around 50 kg (110 lb) of highly enriched uranium in one large rings assembly and one smaller bullet, which was fired down a tube by conventional explosives into the rings assembly to achieve critical mass and detonate the weapon.[ citation needed ]
The W9 units which were retired in 1957 were recycled into lower yield T-4 Atomic Demolition Munitions. These were the first (semi) man-portable nuclear weapons.
The W9 is only the second gun-type nuclear weapon known to have been detonated; the first was the Little Boy nuclear weapon used in World War II.
The W9 artillery shell was test fired once, fired from the "Atomic Annie" M65 Atomic Cannon, in Upshot-Knothole Grable on May 25, 1953 at the NTS. Yield was the expected 15 kilotons.
Subsequently, the W33 nuclear artillery shell was test fired twice (not in a gun) during its development (shots Nougat/Aardvark and Plumbbob/Laplace). These four detonations are the only identified gun-type bomb detonations.
Little Boy is the name of the type of atomic bomb used in the bombing of the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped from the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets Jr., commander of the 509th Composite Group, and Captain Robert A. Lewis. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and had an explosion radius of approximately 1.3 kilometers which caused widespread death across the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity nuclear test.
Nuclear artillery is a subset of limited-yield tactical nuclear weapons, in particular those weapons that are launched from the ground at battlefield targets. Nuclear artillery is commonly associated with shells delivered by a cannon, but in a technical sense short-range artillery rockets or tactical ballistic missiles are also included.
Operation Upshot–Knothole was a series of eleven nuclear test shots conducted in 1953 at the Nevada Test Site. It followed Operation Ivy and preceded Operation Castle.
Operation Plumbbob was a series of nuclear tests that were conducted between May 28 and October 7, 1957, at the Nevada Test Site, following Project 57, and preceding Project 58/58A.
Upshot–Knothole Simon was a nuclear detonation conducted as part of the U.S. Operation Upshot–Knothole nuclear testing program. Simon was conducted on 25 April 1953 at the Nevada Test Site, and tested the TX-17/24 thermonuclear weapon design which had a yield of 43 kilotons.
Gun-type fission weapons are fission-based nuclear weapons whose design assembles their fissile material into a supercritical mass by the use of the "gun" method: shooting one piece of sub-critical material into another. Although this is sometimes pictured as two sub-critical hemispheres driven together to make a supercritical sphere, typically a hollow projectile is shot onto a spike, which fills the hole in its center. Its name is a reference to the fact that it is shooting the material through an artillery barrel as if it were a projectile.
The W19, also called Katie, was an American nuclear artillery shell, derived from the earlier W9 shell. The W19 was fired from a special 11-inch (28 cm) howitzer. It was introduced in 1955 and retired in 1963.
The W33 was an American nuclear artillery shell designed for use in the 8-inch (203 mm) M110 howitzer and M115 howitzer.
Upshot–Knothole Grable was a nuclear weapons test conducted by the United States as part of Operation Upshot–Knothole. Detonation of the nuclear weapon, a W9 warhead, occurred 19 seconds after its deployment at 8:30am PDT on May 25, 1953, in Area 5 of the Nevada Test Site.
The Mark 13 nuclear bomb and its variant, the W-13 nuclear warhead for Redstone BM and Snark CM, were experimental nuclear weapons developed by the United States from 1951 to 1954. The Mark 13 design was based on the earlier Mark 6 nuclear bomb design, which was in turn based on the Mark 4 nuclear bomb and the Mark 3 nuclear bomb used at the end of World War II.
The uranium hydride bomb was a variant design of the atomic bomb first suggested by Robert Oppenheimer in 1939 and advocated and tested by Edward Teller. It used deuterium, an isotope of hydrogen, as a neutron moderator in a uranium-deuterium ceramic compact. Unlike all other fission-bomb types, the concept relies on a chain reaction of slow nuclear fission. Bomb efficiency was harmed by the slowing of neutrons since the latter delays the reaction, as delineated by Rob Serber in his 1992 extension of the original Los Alamos Primer.
A fizzle occurs when the detonation of a device for creating a nuclear explosion grossly fails to meet its expected yield. The bombs still detonate, but the detonation is much weaker than anticipated. The cause(s) for the failure might be linked to improper design, poor construction, or lack of expertise. All countries that have had a nuclear weapons testing program have experienced some fizzles. A fizzle can spread radioactive material throughout the surrounding area, involve a partial fission reaction of the fissile material, or both. For practical purposes, a fizzle can still have considerable explosive yield when compared to conventional weapons.
Upshot-Knothole Dixie was the fourth test-firing of Operation Upshot–Knothole, an atomic weapons test series conducted in 1953 by the United States at the Nevada Test Site.
Upshot–Knothole Harry (UK#9) was a nuclear weapons test conducted by the United States as part of Operation Upshot–Knothole. It took place at the recorded time of 04:05 hours, on May 19, 1953, in Yucca Flat, in the Nevada Test Site. The sponsor of the test was the National Laboratory of the United States of America located at Los Alamos.
Frenchman Flat is a hydrographic basin in the Nevada National Security Site south of Yucca Flat and north of Mercury, Nevada. The flat was used as an American nuclear test site and has a 5.8 sq mi (15 km2) dry lake bed that was used as a 1950s airstrip before it was chosen after the start of the Korean War for the Nevada Proving Grounds. Nellis Air Force Base land 12 mi × 30 mi was transferred to the Atomic Energy Commission on which Site Mercury was constructed on the flat for supporting American nuclear explosive tests. The 1951 Operation Ranger "Able" test was the first continental US nuclear detonation after the 1945 Trinity test, and Frenchman Flat also had the only detonation of an American artillery-fired nuclear projectile in the 1953 Upshot-Knothole Grable test using the M65 Atomic Cannon.
The M65 atomic cannon, often called Atomic Annie, was an artillery piece built by the United States and capable of firing a nuclear device. It was developed in the early 1950s, at the beginning of the Cold War; and fielded between April 1955 and December 1962, in West Germany, South Korea and on Okinawa.
Upshot–Knothole Annie was one of eleven nuclear weapons tests conducted by the United States as part of Operation Upshot–Knothole. It took place at the Nevada Test Site on 17 March 1953, and was nationally televised. The device used in the blast was a 16 kt Mark 5 Nuclear Bomb - a low yield fission weapon, detonated 90 meters / 300 feet above the ground. The live TV coverage was recorded on a kinescope, so it is a rare record of the sound an actual atomic bomb makes.
Upshot–Knothole Encore was a nuclear weapons test conducted by the United States as part of Operation Upshot–Knothole. It took place on May 8, 1953 in Yucca Flat, in the Nevada Test Site.